Hybrid gas insulation switchgear apparatus

ABSTRACT

A hybrid gas insulation switchgear apparatus comprises an enclosure in which an insulating gas is sealed, a bushing unit provided for the enclosure, a breaker unit disposed inside the enclosure, a disconnector unit disposed inside the enclosure and including disconnectors to be connected electrically in series to both sides of the breaker unit, an earth switch unit disposed inside the enclosure and including earth switches disposed between the breaker unit and the disconnectors, respectively, the earth switches being provided with main pole side electrodes disposed on the side of the breaker unit, and a current transformer unit mounted to the enclosure. The bushing unit including bushings each having a conductor connected to an electrode in the disconnector on a side opposite to the breaker.

BACKGROUND OF THE INVENTION

The present invention relates to a switchgear apparatus for powersupply, more particularly, to a hybrid (−type) gas insulation switchgearapparatus with improvement in arrangement of various constitutionalmembers or units including a breaker.

A substation layout includes, as representative examples, one shown in asingle line (connection) diagram of a single bus of FIG. 20, and oneshown in a single line (connection) diagram of one and half bus (1½) ofFIG. 21. In FIGS. 20 and 21, the switchgear apparatus corresponding to aportion surrounded by short dash-lines have similar structures,respectively, in which a breaker 20 and disconnectors 30 disposed onboth ends of the breaker 20 are electrically connected in series.Reference numeral 90 denotes a transformer.

In general, in air substations, since bus and steel tower have longservice lives, the bus or steel tower is less exchanged or replaced at atime of exchanging or replacing the switchgear apparatus. In thisviewpoint, usually, the switchgear apparatus is replaced by another onehaving high performance and high reliability, while effectivelyutilizing an air insulating bus and the like already set in place.

In order to meet such needs, there has so far been proposed a hybrid(−type) gas insulation switchgear apparatus. As an example of hybrid gasinsulation switchgear apparatus, a general hybrid gas insulationswitchgear apparatus will be explained hereunder with reference to anillustration of FIG. 22. The illustrated hybrid gas insulationswitchgear apparatus corresponds to a portion shown with a dash-lineportion in the single-line connection diagrams in FIG. 20 and FIG. 21and is applicable to a double bus type bus connection, though notillustrated.

In other words, the breaker 20 in the hybrid gas insulation switchgearapparatus is operated by an operating mechanism 28 and is equipped witha stationary side electrode 21 and a movable side electrode 22accommodated in an enclosure 81. The breaker 20 is provided with bothside portions to which disconnectors 30 a, 30 b accommodated inenclosures 82 a, 82 b are provided. The disconnectors 30 a, 30 b areconstituted to be capable of being opened or closed (switched) by anoperating mechanism 33. The enclosures 82 a, 82 b are supported by aframe. The breaker 20 and the disconnectors 30 a, 30 b are connectedthrough an adapter conductor 100 accommodated in a vessel.

On the enclosures 82 a, 82 b accommodating the disconnectors 30 a, 30 b,there are fitted the bushings 1 a, 1 b through the insulating spacers63, respectively, and the conductors 11 a, 11 b of the inside bushingsare connected to the disconnectors 30 a, 30 b through conductorsprovided on the insulating spacers 63. Further, an earth switches 4 a, 4b are disposed between the adapter conductor 100 and the disconnectors30 a, 30 b so as to be opened or closed by an operating mechanism 43.Reference numerals 70 a, 70 b denote current transformers.

However, in the conventional hybrid gas insulation switchgear apparatusof the structures mentioned above, the breaker 20 and the disconnectors30 a, 30 b are accommodated respectively independently in the separateenclosures 81, 82 a, and 82 b. Accordingly, the entire size of thedevice is apt to become larger, the weight thereof is also apt to becomeheavier, and product price becomes higher.

SUMMARY OF THE INVENTION

An object of the present invention is to substantially eliminate defectsor drawbacks encountered in the prior art mentioned above and to providea hybrid (type) gas insulation switchgear apparatus or system having acompact and simple structure, which can be easily maintained.

This and other objects can be achieved according to the presentinvention by providing a hybrid gas insulation switchgear apparatuscomprising:

an enclosure in which an insulating gas is sealed;

a bushing unit provided for the enclosure;

a breaker unit disposed inside the enclosure;

a disconnector unit disposed inside the enclosure and includingdisconnectors to be connected electrically in series to both sides ofthe breaker unit;

an earth switch unit disposed inside the enclosure and including earthswitches disposed between the breaker unit and the disconnectors,respectively, the earth switches being provided with main pole sideelectrodes disposed on the side of the breaker unit; and

a current transformer unit mounted to the enclosure,

the bushing unit including bushings each having a conductor connected toan electrode in the disconnector on a side opposite to the breaker.

According to this aspect, the breaker unit, the disconnector unit andthe earth switch unit are accommodated in a single enclosure, andtherefore, it is not necessary to use a long connecting conductors suchas that required in a prior art. Accordingly, it is possible to realizea hybrid gas insulation switchgear apparatus having compact andlight-weight size.

Hereunder, preferred embodiments of the present invention and theiradvantageous functions and effects will be described.

The conductor of the bushing and the electrode of the disconnector aresupported and fixed in the enclosure by an insulating member havingsubstantially a cylindrical or columnar shape.

In the above structure, since the conductor of the bushing is directlyconnected to one side electrode of the disconnector and it is supportedin the enclosure by the cylindrical or columnar insulator, it ispossible to reduce the number of parts of the connector, thereby makingit possible to simplify the assembly working of the apparatus.

A gas space between the enclosure and the bushing unit is sectioned byan insulating member having substantially conical shape, and theelectrode disposed on the side opposite to the breaker unit in thedisconnector is supported by the insulating member.

According to this arrangement, the workability in the checking orinspecting time can be improved.

The enclosure is provided with at least one branch portion, the bushingunit is mounted to the branch portion and at least a set of disconnectorand earth switch is accommodated in the branch portion.

In this structure, since the disconnector and the earth switch areaccommodated in the branch portion, the direct exposure of thedisconnector and the earth switch to the hot gas blown from the breakerat a time of breaking a large current can be prevented. Accordingly, itis possible to improve safeness. In addition, it is possible to shortenthe size of the enclosure for accommodating the breaker.

The enclosure is disposed in a perpendicular direction with respect to aground surface.

According to this arrangement, the installation area of the switchgearapparatus in the horizontal direction can be widely reduced, andmoreover, the insulation distance to the ground of the bushing unit canbe secured easily by the perpendicular arrangement of the enclosure.

Two branch portions are provided in different height levels. The directexposure of the hot gas from the breaker unit at the time of the largecurrent breaking can be prevented by this arrangement.

The two branch portions are provided symmetrically with respect to anaxis of the enclosure at mutually different angles.

According to this arrangement, even if the portion accommodating thebreaker unit in the enclosure is shortened, the air insulation distanceof the bushing unit can be secured, and it is possible to realize thecompact structure of the switchgear apparatus.

The breaker unit is driven by an operating mechanism provided on anextension of an axis of the electrode for the breaker unit.

According to this arrangement, it is possible to transmit the drivingforce of the operating mechanism linearly to the breaker unit, thussimplifying the structure of the driving unit.

The two branch portions are provided in perpendicular direction to theaxis of the enclosure. Accordingly, the entire structure of theswitchgear apparatus can be made compact and simplified.

Two sets of the earth switches and disconnectors are providedhorizontally and in parallel to each other.

According to this structure, since it is possible to save the spaces inthe longitudinal direction of the earth switch and the disconnector andshorten the length of the enclosure, the compact structure of theswitchgear apparatus can be realized.

The disconnectors are driven by a single operating mechanism.Accordingly, the switchgear apparatus can be also made compact and thecontrol system can be simplified.

A driving force transmitting device for transmitting a driving force ofthe operating mechanism to the two disconnectors is accommodated in theenclosure. Thus, the gas-tightness to the insulating gas can be easilysecured.

The enclosure is disposed in a horizontal direction with respect to theground level, two branch portions accommodating the disconnectors areprovided on an upper portion of the enclosure, an operating mechanism isset at substantially a central portion of the branch portions on theupper portion of the enclosure, and the two disconnectors disposedinside the branch portions and the operating mechanism are connectedthrough an operating rod.

According to this arrangement, since the driving force transmissionroute can be provided on the straight line, the switchgear apparatus canbe simplified in arrangement.

Furthermore, the disconnector unit and the earth switch unit areprovided to be driven by a single operating mechanism.

In this arrangement, it is possible to curtail the number of theoperating mechanisms, and therefore, it becomes possible to makesimplified the entire structure of the switchgear.

The nature and further characteristic features of the present inventionwill be made more clear from the following descriptions made withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a schematic elevational section of a hybrid gas insulationswitchgear apparatus according to a first embodiment of the presentinvention;

FIG. 2 is a single-line connection diagram (one-line diagram) of FIG. 1;

FIG. 3 is a schematic elevational section of a hybrid gas insulationswitchgear apparatus according to a second embodiment of the presentinvention;

FIG. 4 is a schematic elevational section of a hybrid gas insulationswitchgear apparatus according to a third embodiment of the presentinvention;

FIG. 5 includes FIG. 5A being a side view and FIG. 5B being a front viewof the hybrid gas insulation switchgear apparatus of a fourth embodimentof the present invention;

FIG. 6 includes FIG. 6A being a plan view viewed from an arrow VIA inFIG. 6B, which is a sectional view taken along the line VIB—VIB in FIG.6A of the hybrid gas insulation switchgear apparatus according to afifth embodiment of the present invention;

FIG. 7 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus according to a sixth embodiment of the presentinvention;

FIG. 8 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus according to a seventh embodiment of the presentinvention;

FIG. 9 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus according to a eighth embodiment of the presentinvention;

FIG. 10 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus according to a ninth embodiment of the presentinvention;

FIG. 11 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus according to a tenth embodiment of the presentinvention;

FIG. 12 includes FIG. 12A being a plan view viewed from an arrow XIIA inFIG. 12B, which is a sectional view taken along the line XIIB—XIIB inFIG. 12A of the hybrid gas insulation switchgear apparatus according toan eleventh embodiment of the present invention;

FIG. 13 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus in a twelfth embodiment of the present invention;

FIG. 14 are illustrations including FIG. 14A showing a grounding state,FIG. 14B showing a state of closed disconnector; and FIG. 14C showing astate of opened disconnector;

FIG. 15 is a schematic elevational view of the hybrid gas insulationswitchgear apparatus according to a thirteenth embodiment of the presentinvention;

FIG. 16 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus according to fourteenth embodiment of the presentinvention;

FIG. 17 includes FIG. 17A showing a schematic side view and FIG. 17Bshowing a schematic front view of the hybrid gas insulation switchgearapparatus according to a fifteenth embodiment of the present invention;

FIG. 18 is a schematic elevational section of the hybrid gas insulationswitchgear apparatus according to a sixteenth embodiment of the presentinvention;

FIG. 19 includes FIG. 19A showing a schematic plan view, partially insection viewed from an arrow XIXA in FIG. 19B, which showing a schematicfront view of the hybrid gas insulation switchgear apparatus of FIG. 19Aaccording to a seventeenth embodiment of the present invention;

FIG. 20 is a single-line (connection) diagram in a single bus system;

FIG. 21 is a single-line (connection) diagram in one and half (1½)system; and

FIG. 22 is a schematic elevational section showing an example of aconventional hybrid gas insulation switchgear apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of hybrid gas insulation switchgear apparatus ofthe present invention will be described hereunder with reference toFIGS. 1 to 19, in which like reference numerals are added to elements ormembers corresponding to those shown in FIGS. 20 to 22 showing theconventional example. Further, it is to be noted that the terms such as“upper”, “lower”, “vertical”, “horizontal” and the like are used hereinwith reference to the illustrated state or to ground level.

1. First Embodiment

1-1. Constitution

A first embodiment of the present invention will be first described withreference to FIGS. 1 and 2. A hybrid (−type)gas insulation switchgearapparatus of this first embodiment comprises bushings 1 a, 1 b and anenclosure 80 in which a breaker 20, disconnectors 30 a, 30 b and earthswitches 40 a, 40 b are accommodated. Further, current transformers 70a, 70 b are provided for the enclosure 80. The breaker 20 is equippedwith a stationary side electrode 21 and a movable side electrode 22. Themovable side electrode 22 is constructed to be driven by an operatingmechanism 27 mounted on the enclosure 80 through an operation rod 24, aconversion lever 25 and a movable side rod 26. Further, the breaker 20is supported and fixed in the enclosure 80 by a supporting insulator 23.

The disconnectors 30 a, 30 b are connected in series to both sides ofthe breaker 20 and equipped with movable side electrodes 31 andstationary side electrodes 32. The movable side electrodes 31 areconstituted to be driven through the operating rods 34 by operatingmechanisms 33 mounted to the enclosure 80, and the movable sideelectrodes 31 are supported by cylindrical insulators 60 a, 60 b mountedto the enclosure 80. Further, to the stationary side electrodes 32,there are provided main pole side electrodes 41 of the earth switches 40a, 40 b, respectively. This main pole side electrode 41 is connected tothe breaker 20. The movable side electrodes 42 of the earth switches 40a, 40 b are constructed to be driven by operating mechanisms 43 mountedon the enclosure 80.

In addition, branch portions are provided on the right and left sides ofthe upper portion (in the illustration of FIG. 1) of the enclosure 80,and insulators (insulation tubes) of the bushings 1 a, 1 b are fixed tothe ends of the branch portions, respectively. The bushings 1 a, 1 b areprovided with conductors 11 a, 11 b connected to the movable sideelectrodes 31 of the disconnectors 30 a, 30 b, respectively. The currenttransformers 70 a, 70 b for identifying an accident are mounted to thebranch portions of the enclosure 80.

1-2. Function and Effect

According to this first embodiment of the structures mentioned above,since the breaker 20, the disconnectors 30 a, 30 b, and the earthswitches 40 a, 40 b are accommodated in the single enclosure 80, theswitchgear apparatus as a whole can be formed into a compact size.

In addition, since the kinds and number of the enclosures can bereduced, it becomes unnecessary to use additional buses for connectingdevices or units to each other as in the conventional structure. Thus,it is possible to make the apparatus lightweight and low priced and tomake simple the entire structure of the switchgear apparatus.Especially, in this embodiment, since the disconnectors 30 a, 30 b arearranged on both sides of the breaker 20, the structure of thisembodiment may be effectively applicable to the single bus, one and half(1 ·½) CB system in the substation constitution for which the hybridtype gas insulation, switchgear apparatus is used.

Furthermore, since the conductors 11 a, 11 b of the bushings 1 a, 1 band the movable side electrodes 31 of the disconnectors 30 a, 30 b aresupported and fixed in the insulated manner by the cylindricalinsulators 60 a, 60 b mounted to the enclosure 80, it is possible toomit conductors of insulating spaces sectioning the enclosure 80 fromthe bushings 1 a, 1 b to thereby make it possible to directly connectthe conductors 11 a, 11 b of the bushings 1 a, 1 b to the electrodes ofthe disconnectors 30 a, 30 b. Accordingly, it is possible to reduce thenumber of parts of the connecting members and simplify the constitutionand assembly steps or processes.

2. Second Embodiment

2-1. Constitution

A second embodiment of the present invention will be described hereunderwith reference to FIG. 3. This second embodiment has a structurebasically identical to that of the first embodiment with an exceptionthat, in this second embodiment, two sets of disconnectors 30 a, 30 bconnected in series on both sides of the breaker 20 and earth switches40 a, 40 b are accommodated respectively in two branch portions providedon an upper portion of the enclosure 80.

2-2. Function and Effect

According to this second embodiment, since the disconnectors 30 a, 30 band the earth switches 40 a, 40 b are accommodated respectively in thebranch portions, the disconnectors 30 a, 30 b and the earth switches 40a, 40 b can be prevented from being directly exposed to a hot gas blownfrom the breaker 20, thus improving safe operation and workings.Furthermore, a main barrel portion of the enclosure 80 for accommodatingthe breaker 20 can be made short in length, so that the hybrid gasinsulation switchgear apparatus can be made small in size andmanufactured with a reduced cost.

3. Third Embodiment

3-1. Constitution

A third embodiment of the present invention will be described hereunderwith reference to FIG. 4. This third embodiment has a structurebasically identical to that of the second embodiment. In this thirdembodiment, however, an operating mechanism 27 for driving a movableside electrode 22 of the breaker 20 is arranged on one side in thelongitudinal direction of the enclosure 80, and an operating rod 24 isarranged on a horizontal line. In addition, a cylindrical insulator 64for supporting the breaker 20, the earth switch 40 a and the stationaryside electrode 32 of the disconnector 30 a is arranged on the insidesurface of the enclosure 80.

3-2. Function and Effect

According to this third embodiment, functions and effects similar tothose of the second embodiment are obtainable, and it is possible toarrange the operating rod 24 for driving the breaker 20 on a straightline and to thereby omit the members for converting the drivingdirection. Accordingly, the structure of the driving unit can be largelysimplified.

4. Fourth Embodiment

4-1. Constitution

A fourth embodiment of the present invention will be described hereunderwith reference to FIGS. 5A and 5B. This fourth embodiment has astructure basically identical to that of the second embodiment with anexception that, as shown in FIG. 5B, the branched portions of theenclosure 80 are arranged, at angles different from each other, axiallysymmetrically to the enclosure 80 in a manner that the front ends of thebushings 1 a, 1 b are directed to the mutually separating directions.

4-2. Function and Effect

According to this fourth embodiment, functions and effects similar tothose of the second embodiment will be obtainable, and since thebranched portions are provided in the mutually separating directions,the air insulating distance between the bushings 1 a and 1 b can besecured even when the main barrel portion of the enclosure 80 isconstructed to be short. Therefore, it is possible to provide a hybridgas insulation switchgear apparatus having small and compact size, morelight weight at a low manufacturing cost while maintaining the safenessof the apparatus.

5. Fifth Embodiment

5-1. Constitution

A fifth embodiment of the present invention will be described hereunderwith reference to FIGS. 6A and 6B, in which FIG. 6A is a view from anarrow VIA in FIG. 6B and FIG. 6B is a sectional view taken along theline VIB—VIB in FIG. 6A. In this fifth embodiment, although the breaker20 and the two sets of disconnectors 30 in the first embodiment are notarranged on the same straight line, the disconnectors 30 a, 30 b and theearth switches 40 a, 40 b are arranged to be parallel to each other. Theconductor connected to the movable side electrode 22 of the breaker 20extends so as to be turned back and are connected to the stationary sideelectrode 32 of the disconnector 30 b. Furthermore, two branch portionsare formed at side end portions in the longitudinal direction of theupper portion of the enclosure 80, and the bushings 1 a, 1 b are mountedto the branch portions, respectively.

5-2. Function and Effect

According to this fifth embodiment, functions and effects similar tothose of the first embodiment will be obtainable. Moreover, since thespace in the longitudinal direction of the disconnectors 30 a, 30 b canbe saved and the length of the main barrel portion of the enclosure 80can be shortened, it becomes possible to make compact and simple wholethe switchgear apparatus.

6. Sixth Embodiment

6-1. Constitution

A sixth embodiment of the present invention will be described hereunderwith reference to FIG. 7. It is to be noted that this sixth embodimentis basically similar to the first embodiment in the point that two setsof disconnectors 30 a, 30 b and earth switches 40 a, 40 b arerespectively connected in series on both sides of the breaker 20.However, in this sixth embodiment, the enclosure 80, in which thebreaker 20, the disconnector 30 a and the earth switch 40 a areaccommodated, is disposed in a perpendicular direction with respect tothe ground level G.

On the lateral surface of the enclosure 80 mentioned above, there isprovided a branch portion oriented obliquely upward. In the branchportion, the disconnector 30 b and the earth switch 40 b areaccommodated. Further, at the end of the enclosure 80, the bushing 1 aand the current transformer 70 a are mounted, and at the other branchedend portion of the enclosure 80, another bushing 1 b and currenttransformer 70 b are also mounted.

6-2. Function and Effect

According to this sixth embodiment, function and effects similar tothose of the first embodiment will be obtainable, and moreover, theconductor structure can be simplified, while the entire structure of theswitchgear apparatus being made largely compact. Accordingly, it becomespossible to make compact and simple the whole apparatus at lowmanufacturing cost. In addition, it becomes possible to easily ensurethe distance of insulation to the earth of the bushings 1 a, 1 b, thusimproving safeness.

7. Seventh Embodiment

7-1. Constitution

A seventh embodiment of the present invention will be describedhereunder with reference to FIG. 8. This seventh embodiment basicallyhas a structure similar to that of the sixth embodiment. In this seventhembodiment, however, two branch portions having different heights areprovided in mutually separating directions on the side surfaces ofenclosures 80 accommodating the breakers 20. In these branch portions,there are accommodated the disconnectors 30 a, 30 b and the earthswitches 4 a, 4 b, respectively.

7-2. Function and Effect

According to this seventh embodiment, functions and effects similar tothose of the sixth embodiment will be obtainable, and, due to theprovision of differences in the height of the two branch portions, thedisconnectors 30 a, 30 b and the earth switches 40 a, 40 b are notdirectly exposed to the hot gas blown from the breaker 20 at thebreakage of the large current.

8. Eighth Embodiment

8-1. Constitution

An eighth embodiment of the present invention will be described withreference to FIG. 9. This eighth embodiment has a structure basicallysimilar to that of the first embodiment. However, in order to allowdisconnectors 30 a, 30 b to be driven by a single operating mechanism33, one of the operating rods 34 a of the operating mechanisms 33 isconnected to the movable side electrode 31 of the disconnector 30 a andthe other one of the operating rods 34 b of the operating mechanism 33is connected to the movable side electrode 31 of the disconnector 30 bthrough the driving direction converter and the operating rod 34 c. Theoperating rod 34 b is disposed in the horizontal direction on the lowerportion of the enclosure 80.

8-2. Function and Effect

According to this eighth embodiment, one of two operating mechanisms,which had been required in the prior art, can be eliminated, so that theswitchgear apparatus can be simplified. Furthermore, since it ispossible to curtail the number of the auxiliary contacts and theterminal tables to be transferred to the control board, a control systemfor the switchgear apparatus can be simplified, and it becomes possibleto simplify the sequence in which mutual relation of the machinery canbe grasped because the operations of the electric apparatus arerepresented according to its sequential order.

Furthermore, the disconnectors 30 a, 30 b at both ends of the breaker 20are to be operated under the conditions that the breaker 20 has alreadybeen opened, and even if the two disconnectors 30 a, 30 b at both endsof the breaker 20 are independently operated, there is no change in thecable run, so that there causes no problem even if the two disconnectorsare simultaneously driven by the same operating mechanism.

9. Ninth Embodiment

9-1. Constitution

A ninth embodiment of the present invention will be described hereunderwith reference to FIG. 10. This ninth embodiment has a structurebasically similar to that of the first embodiment. However, in thisninth embodiment, one operating mechanism 33 is provided on one end sideof the enclosure 80 in the longitudinal direction, and a driving forcetransmitting device is disposed in the enclosure 80 so as to allowdisconnectors 30 a, 30 b to be driven by the operating mechanism 33.This driving force transmitting device comprises an operation rod 34disposed in parallel to the axis of the enclosure 80 and transmittingsections 34 d, 34 e for transmitting the driving force of the operationrods 34 to the disconnectors 30 a, 30 b through driving force branchingdevices 35.

9-2. Function and Effect

According to this ninth embodiment, functions and effects similar tothose of the eighth embodiment will be obtainable, and since theoperating rod 34 inside the enclosure 80 is driven by the operatingmechanism 33 in air and the two disconnectors 30 a, 30 b are driven bybranching the driving force inside the enclosure 80, it is possible tocurtail the place at which air-tightness preservation of the insulatinggas is required and to easily maintain the air-tightness.

10. Tenth Embodiment

10-1. Constitution

A tenth embodiment of the present invention will be described hereunderwith reference to FIG. 11. This tenth embodiment has a structurebasically similar to that of the second embodiment. However, in thistenth embodiment, an operating mechanism 33 is provided at approximatelythe central portion of the two branch portions on the upper portion ofthe enclosure 80, and the movable side electrode 31 of disconnectors 30a, 30 b is connected to the operating mechanism 33 through an operatingrod 34 so as to allow the disconnectors 30 a, 30 b to be driven by theoperating mechanism 33. Further, earth switches 40 a, 40 b are providedin the enclosure 80.

10-2. Function and Effect

According to this tenth embodiment, functions and effects similar tothose of the eighth embodiment will be obtainable, and since theoperating mechanism 33 is provided at the central portion of the twobranch portions, it becomes unnecessary to use gearwheels or the likefor converting the driving force on the transmission axis, and hence,the switchgear apparatus can be simplified in the eitire structure.

11. Eleventh Embodiment

11-1. Constitution

An eleventh embodiment of the present invention will be describedhereunder with reference to FIG. 12 (FIGS. 12A and 12B). This eleventhembodiment has a structure basically similar to that of the fifthembodiment. However, in this embodiment, one operating mechanism 33 isarranged on one side surface of the enclosure 80, and the movable sideelectrode 31 of disconnectors 30 a, 30 b is connected to the operatingmechanism 33 through the operating rod 34 so that the two disconnectors30 a, 30 b can be driven by the operating mechanism 33.

11-2. Function and Effect

According to this eleventh embodiment, functions and effects similar tothose of the fifth and eighth embodiments will be obtainable, and sincethe two disconnectors 30 a, 30 b are arranged in parallel to each otherat relatively near portions, a collective driving inside the enclosure80 by means of the operating mechanism 33 can be facilitated, thusmaking the structure more simplified.

12. Twelfth Embodiment

12-1. Constitution

A twelfth embodiment of the present invention will be describedhereunder with reference to FIG. 13 and FIG. 14. FIG. 14 is a view froman arrow of XIVA in FIG. 13 and includes FIGS. 14A, 14B and 14C showinga grounding state, a closed electrode condition of the disconnector, andan open electrode condition of the disconnector, respectively. Thisembodiment has a structure basically similar to that of the firstembodiment. However, in this embodiment, two disconnectors 30 a, 30 bhave the functions of the earth switches, and all of them are providedas can be driven by the single operating mechanism 33. More concretely,as shown in FIG. 13, the single operating mechanism 33 is provided onthe lower surface of the enclosure 80, and there are providedtransmitting sections 34 d, 34 e for transmitting the driving force tothe movable side electrodes 31 of the disconnectors 30 a, 30 b throughthe operating rod 34 and the driving force branching devices 35, so thatthe disconnectors 30 a, 30 b can be driven by the operating mechanism33.

The movable side electrodes 31 of the disconnectors 30 a, 30 b areconstituted, as shown in FIG. 14A, to be in contact with the earthelectrode 80 a provided on the enclosure 80 under the grounding state,as shown in FIG. 14B, to be in contact with the stationary sideelectrode 32 of the disconnectors 30 a, 30 b, and further, as shown inFIG. 14C, under the open electrode state of the disconnector, to beseparated from the earth electrode 80 a and the stationary sideelectrode 32.

12-2. Function and Effect

According to this embodiment, substantially the same function and effectas those of the first and eighth embodiments are obtainable, and threeof the four operating mechanisms 33 conventionally required can beomitted. Therefore, a greater simplification of the structure can berealized.

13. Other Embodiments

The present invention is not limited to the embodiments as mentionedabove. Namely, there is provided an embodiment corresponding to theinvention of the ninth embodiment, and in this embodiment, as shown inFIG. 15, the supporting and fixing of the conductors 11 a, 11 b of thebushings 1 a, 1 b and the movable side electrode 31 of the disconnectors30 a, 30 b of the first embodiment are made by approximately columnarinsulators 62 a, 62 b provided on the enclosure 80 instead of thecylindrical insulator of the first embodiment. According to suchembodiment, the constitutional members or parts can be made small andthe entire structure of the switchgear apparatus can be made simplified.

Furthermore, in another embodiment shown in FIG. 16, a gas space betweenthe bushings 1 a, 1 b and the enclosure 80 in the first embodiment issectioned, and approximately conical insulators 63 a, 63 b forconnection and supporting the conductors 11 a, 11 b with the movableside electrode 31 of the disconnectors 30 a, 30 b are disposed in thebranched portion of the enclosure 80. According to this embodiment,workability at the time of checking or inspecting the switchgearapparatus can be improved.

Furthermore, in an embodiment shown in FIGS. 17A and 17B, the branchportion of the enclosure 80 in the seventh embodiment may be providedapproximately vertically to the axis of the enclosure 80, by which theconstitution of the enclosure 80 can be simplified to therebymanufacture the switchgear apparatus at low cost.

Still furthermore, in an embodiment corresponding to the invention ofthe third embodiment, as shown in FIG. 18 and FIGS. 19A and 19B, thethird embodiment may be applied to the fourth and fifth embodiments.That is, in this case, the operating mechanism 27 for driving themovable side electrode 22 in the breaker 20 is disposed (displaced) onone side in the longitudinal direction of the enclosure 80 and theoperating rod 24 is arranged on a horizontal straight line. Further, acylindrical insulator 64 for supporting the breaker 20, the earth switch40 a, and the stationary side electrode 32 of the disconnector 30 a isprovided inside the enclosure 80. According to such arrangement, theoperating rod 24 for driving the breaker 20 can be arranged on astraight line, which makes simple the constitution of the driving unit.

As described hereinbefore, according to the present invention, it ispossible to provide a compact, simple and low priced hybrid gasinsulation switchgear apparatus.

It is to be noted that the present invention is not limited to thedescribed embodiments and many other changes and modifications may bemade without departing from the scopes of the appended claims.

What is claimed is:
 1. A hybrid gas insulation switchgear apparatuscomprising: an enclosure in which an insulating gas is sealed; a bushingunit provided for the enclosure; a breaker unit disposed inside theenclosure; a disconnector unit disposed inside the enclosure andincluding disconnectors to be connected electrically in series to bothsides of the breaker unit; an earth switch unit disposed inside theenclosure and including earth switches disposed between the breaker unitand the disconnectors, respectively, and said earth switches beingprovided with main pole side electrodes disposed on the side of thebreaker unit; and a current transformer mounted to the enclosure,wherein: said bushing unit including bushings each having a conductorconnected to an electrode of the disconnector on a side opposite to thebreaker, said enclosure and said bushing unit defines a spacetherebetween which sectioned by an insulating member havingsubstantially conical shape, and said electrode disposed on the sideopposite to the breaker unit in the disconnector is supported by theinsulating member, said enclosure is provided with at least one branchportion, the bushing unit being mounted to the branch portion and atleast a set of disconnector and earth switch is accommodated in thebranch portion, and two branch portions are provided in different heightlevel with an inclination with respect to an axis of the enclosure. 2.The hybrid gas insulation switchgear apparatus according to claim 1,wherein said two branch portions are provided with an inclinationsymmetrically with respect to the axis of said enclosure at mutuallydifferent angles.
 3. The hybrid gas insulation switchgear apparatusaccording to claim 1, wherein said two branch portions are provided withan inclination in a perpendicular direction to the axis of theenclosure.
 4. The hybrid gas insulation switchgear apparatus accordingto claim 1, wherein said breaker unit is driven by an operatingmechanism provided on an extension of an axis of the electrode for thebreaker unit.
 5. The hybrid gas insulation switchgear apparatusaccording to claim 1, wherein said disconnectors are driven by a singleoperating mechanism.
 6. The hybrid gas insulation switchgear apparatusaccording to claim 5, wherein said enclosure is disposed in horizontaldirection with respect to the ground level, two branch portionsaccommodating the disconnectors are provided on an upper portion of theenclosure, an operating mechanism is set at substantially a centralportion of the branch portions on the upper portion of the enclosure,and said two disconnectors disposed inside the branch portions and theoperating mechanism are connected through an operating rod.